Economic and greenhouse gas assessments for two hot water industrial systems: Solar vs. natural gas

Abstract

Recognizing the energy-intensive character of the industrial sector, especially for process heat, this study designs two hot water systems for a textile industry located in Northeast Brazil. Then both systems are compared from financial and environmental viewpoints. The economic analysis uses the Payback period, Internal Rate of Return, and Net Present Value. The environmental analysis uses the Life Cycle Assessment methodology to quantify the greenhouse gas emissions associated with building and operating both systems. The economic analysis confirms that the solar water heating system is viable, with a profitability rate of 29.46, which makes it an attractive investment. The accountancy of greenhouse gases confirmed the potential of the solar system to mitigate climate change, with overall annual emissions 50 times lower than the natural gas system. The results obtained are highly related to sustainable development and cleaner production, and can be employed by decision makers aiming to change consumption and production patterns towards a more sustainable future. • Two water heating systems are designed for a textile industry. • Greenhouse gas emissions are quantified for both systems. • The solar system emits 643 kg CO 2 -eq/year with a financial payback of 5 months. • The natural-gas system emits 33,000 kg CO 2 -eq/year. • Profitability rate of the solar system is 29.46, confirming economic viability.